Micro bio ch.7

Gene

Functional unit of a genome

Genome

Set of genetic information in a cell

Genomics

The study of nucleotides in DNA sequences

Central dogma

Genetic info flows from DNA to RNA and using translation from RNA to build proteins

DNA

The double-stranded helix, sugar phosphate, and strands are complementary by hydrogen

RNA

Ribose = deoxyribose; uracil instead of thymine, shorter single stand from DNA strand

Messenger RNA (mRNA)

Encodes proteins and transcribes

Ribosomal RNA (rRNA)

Form ribosome performs protein synthesis

Transfer RNA (tRNA)

Bring amino acids to make new proteins

DNA replication ink prokaryotes

It is bidirectional from the origin of replication

Semi-conservative replication

One from the original strand and one new strand

Helicases

Unwind/unzip DNA helix into one strand

DNA gyrase

Breaks strands and relaxes to prevent supercoiling

Premases

Add RNA sequences that complement DNA, also called primers

DNA polymerases

Removes RNA

DNA ligases

Seal gaps between gaps in lagging strands

Leading strand synthesis

New strand made continuously from 5-3, polymerase adds complementary from 3-5

Lagging strand synthesis

Complicated, 3-5 polymerase cannot synthesize, discontinuous. Okazaki fragments

Transcription

RNA polymerase synthesizes single-strand RNA from DNA as a template

Initiation of transcription

Bind to promoter, sigma factor to see sequences

Elongation of transcription

Moves along DNA reading template, adds 3 to end

Termination of transcription

RNA polymerase falls off, releasing RNA

Translation

Decoding info from RNA sequence in mRNA

Codon

Triplet from combo of four nucleotides

Amino acids

61 codons will translate to 20 amino acids

Initiation of translation

Ribosome binds to mRNA sequences that complement called ribosome binding site

Elongation of translation

tRNA, next codon goes to A-site. Creates peptide bond. Exits from E site

Termination of translation

Stop codon

A-T, G-C (DNA)

Base pairing in DNA

A-U, T-A, G-C (RNA)

Base pairing in RNA

Mutation

Change in nucleotide sequence

Horizontal gene transfer

Movement of DNA from one organism to another

Genotype

Sequence of nucleotides in DNA

Phenotype

Observable, physical traits determined by genotype

Spontaneous mutation

Random changes from normal cell processes

Base pair substitutions

Most common mutation, point mutation that changes a single pair

Synonymous (silent mutation)

Codes for the same amino acid

Missense mutation

Creates a codon for different amino acids

Nonsense mutation

Creates a stop codon

Frameshift mutation

Where one or more nucleotides are added or deleted from the sequence, disrupting the reading frame

Transposing

Pieces of DNA that can move.